Effect of transforaminal lumbar interbody fusion on spinopelvic parameters in degenerative spondylolisthesis and its correlation to patient-reported functional outcome

Background: Degenerative spondylolisthesis (DS) is associated with altered radiological spinopelvic parameters (SPP) which leads to poor patient-reported clinical outcomes. Transforaminal lumbar interbody fusion (TLIF) is performed for DS however, its ability to adequately restore SPP is not well reported. The study was performed to determine the effect of TLIF on the SPP and its correlation to patient-reported functional outcomes. Materials and Methods: Prospective, consecutive recruitment of patients was performed, with single and double-level DS treated with TLIF between March 2019 to March 2020 with a 2-year follow-up. Functional outcomes were measured using the visual analog score (VAS) score, Oswestry Disability Index (ODI) score, and SF-36 questionnaire. SPPs (pelvic tilt [PT], pelvic inclination, sacral slope [SS], lumbar lordosis [LL], and PI-LL mismatch) were recorded. The correlation between SPP and functional outcomes was analyzed using Spearman’s correlation coefficient. Results: A total of 40 patients were included in the final analysis. Significant improvement in VAS score, ODI score, and SF-36 score was observed (P < 0.05 for all) at 2 years follow-up. No significant difference was noted in the PI, LL, and SS following surgery (P > 0.05). A significant change in mean PT from 15.76° to 19.53° was noted (P = 0.023). The mean PI-LL mismatch improved from 14.7° to 11.2° which was statistically significant (P < 0.05). However, no significant correlation between ODI score with PT (r = 0.156) and post-op PI-LL mismatch (r = 0.105) could be demonstrated. Conclusion: TLIF led to satisfactory improvement in the patient-reported outcomes, PT, and PI-LL mismatch. However, the improvement of the SPP did not correlate with improvements in the ODI score.